The rubber gloves which are used in a variety of field, such as housework, food industry, electronic industry, medical field have been made by molding natural rubber. However, in recent years, the natural rubber is limited in its use due to the problem of allergies of natural protein of natural rubber and its unstable supply and demand.
Therefore, rubber gloves made by dip-molding the latex composition produced by blending sulfur and a vulcanization accelerator to synthetic rubber latices without causing allergic reaction, such as a carboxylic acid-modified nitrile based copolymer latex of a acrylic acid-acrylonitrile-butadiene copolymer latex, etc., are widely used.
Rubber gloves made from these sulfur S and the vulcanization accelerators can have good durability and improved strength to the extent that rubber gloves do not break easily even if they are used for a long time, as the sulfur forms cross-linking between the polymer chains,
However, rubber gloves prepared with carboxylic acid-modified nitrile-based copolymer latex have less elasticity than those prepared with natural rubber, and thus are limited for use in gloves where wearing sensation is important, such as surgical gloves.
Therefore, studies have been carried out to increase the content of AN or reduce the amount of acid used in carboxylic acid-modified nitrile-based copolymer latex. However, there is a problem that not only a large amount of coagulum is generated due to deterioration of the stability of the latex polymerization and thus stable polymerization is difficult, but also the rubber gloves prepared using the latex exhibit high modulus and thus the wearing sensation of the gloves is deteriorated. In addition, studies have been carried out to improve the elasticity by mixing latex with high glass transition temperature with carboxylic acid-modified nitrile based copolymer latex, but there is a great disadvantage that degradation of physical properties such as high modulus and low elongation compared to improvement of elasticity is generated.
In addition, when preparing the rubber gloves using sulfur and a vulcanization accelerator, it is required to carry out a long stirring and aging process for 24 hours or more, and thus there is a problem that the productivity is lowered. In addition, in the case of the rubber gloves formed by blending sulfur and the vulcanization accelerator as essential component, when wearing it for a long time and continuing work, unpleasant odor is generated due to sulfur, or discoloration of rubber gloves occurs, resulting in deterioration of the product value. Also, for some users, there is a problem that an allergic reaction is induced and skin irritation such as tingling is caused. Therefore, studies are underway to prepare rubber gloves with good durability without causing problems such as discomfort, discoloration, and allergic reactions in use, by not using sulfur and the vulcanization accelerator.
As an example, a rubber glove was studied that does not require a long stirring and aging process and does not cause discoloration by using latex composition for dip-molding including a conjugated diene rubber latex and organic peroxide. However, at this time, there are disadvantages that the solution of organic peroxide is very harmful to the human body and can cause fire and explosion when heat or impact is applied, and thus, process safety is very low.
In addition, a rubber glove that does not cause allergic reactions have been developed by sulfur and a vulcanization accelerator using a cross-linkable monomer along with an acrylic emulsion latex without the long stirring and aging process, but there is a problem that the physical properties are degraded by the timeelapes of the cross-linkable monomer.
As described above, it is very difficult to prepare a carboxylic acid-modified nitrile based latex which satisfies all of the above-mentioned characteristics opposite to each other in nitrile gloves of various fields, and there is a limit in preparing such a latex using the existing latex composition.